share main loop iter logic with emscripten_*_loop and glut
Merge branch 'incoming' into proxyGL
skip a frame if Module.preMainLoop returns false
skip main loop iterations when gl buffer is stalled, instead of gl frames which may be incorrect to drop
trigger reftest from requestAnimationFrame, for worker-proxied code
cubegeom proxy test
cleanup
fix browser.test_glgears_proxy
support --proxy-to-worker with js target, emitting 2 files for client and worker
fake document.styleSheets
more prefetched parameters
deleteShader, deleteProgram
another prefetched parameter
return 0 in gl emulation code for GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT
clearDepth, depthFunc, frontFace, cullFace
fake canvas.exitPointerLock
don't open files with empty path
Add test case for empty path

Test case credits to wilkie from -
https://github.com/kripken/emscripten/issues/2235
simplify proxy testing
abort on readPixels in worker